Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2013 Distribution range and ecological niche of Primula marginata Curtis (Primulaceae) Casazza, Gabriele ; Marsili, Stefano ; Granato, Laura ; Conti, Elena ; Noble, Virgile ; Selvaggi, Alberto ; Minuto, Luigi Abstract: The distribution range of Primula marginata Curtis (Primulaceae) has never been fully char- acterized. In the present study, authors did a revision of the distribution range using herbaria material, database records and in situ populations’ check-up. P. marginata was confirmed extending from Cottian to Maritime and Ligurian Alps, with few outlier occurrences in the northern Apennines. The locali- ties previously reported from northern Piedmont (Val d’Ossola) were not confirmed. Maximum entropy model (Maxent) was used to simulate the potential distribution of P. marginata under current climate conditions. According to the distribution modelling performed, the species prefers rocky calcareous habi- tats mainly at high elevations, with abundant precipitation, but low moisture retention at soil level and marked temperature range between winter and summer seasons. The potential distribution area drawn by Maxent seemed to describe P. marginata at its maximum extension, and any future climate changes might cause limitations for the survival of the species. DOI: https://doi.org/10.1080/11263504.2012.760495 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-74992 Journal Article Accepted Version Originally published at: Casazza, Gabriele; Marsili, Stefano; Granato, Laura; Conti, Elena; Noble, Virgile; Selvaggi, Alberto; Minuto, Luigi (2013). Distribution range and ecological niche of Primula marginata Curtis (Primulaceae). Plant Biosystems, 147(3):593-600. DOI: https://doi.org/10.1080/11263504.2012.760495 Running title: Distribution range and ecological niche of P. marginata Corresponding author: Gabriele Casazza University of Genova,DISTAV – Polo Botanico Hanbury C.so Dogali 1M, I-16136 Genova, Italy Phone: +390102099370 Fax +390102099377 E-mail: [email protected] Accepted Manuscript Distribution range and ecological niche of Primula marginata Curtis (Primulaceae) 1 1 1 2 CASAZZA GABRIELE *, MARSILI STEFANO , GRANATO LAURA , CONTI ELENA , NOBLE 3 4 1 VIRGILE , SELVAGGI ALBERTO AND MINUTO LUIGI 1 DIP.TE.RIS., University of Genoa, Corso Dogali 1M, I-16136, Genoa, Italy 2 Institut für Systematische Botanik - Universität Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland. 3 Conservatoire Botanique National Méditerranéen de Porquerolles, 76A Avenue Gambetta F-83400 Hyères, France / Institut Méditerranéen d’Ecologie et de Paléoécologie (IMEP, UMR CNRS 6116), Aix-Marseille University (Université Paul Cézanne), Europôle Méditerranéen de l’Arbois, F-13100 Aix-en-Provence, France. 4 Istituto per le Piante da Legno e l'Ambiente - IPLA spa, Corso Casale 476, I-10132 Torino, Italy. * Corresponding author. E-mail: [email protected] Abstract: The distribution range of Primula marginata Curtis (Primulaceae) has never been fully characterized. In the present study authors did a revision of the distribution range using herbaria material, database records and in situ populations check-up. P. marginata was confirmed extending from Cottian to Maritime and Ligurian Alps, with few outlier occurrences in the northern Apennines. The localities previously reported from northern Piedmont (Val d’Ossola) were not confirmed. Maximum entropy model (Maxent) was used to simulate the potential distribution of P. marginata under current climate conditions. According to the distribution modelling performed, the species prefersAccepted rocky calcareous habitats mainly Manuscriptat high elevations, with abundant precipitation, but with low moisture retention at soil level and marked temperature range between winter and summer seasons. The potential distribution area drawn by Maxent seemed to describe P. marginata at its maximum extension and any future climate changes might cause limitations for the survival of the species. Keywords: Distribution range, ecological niche, Western Alps, Primula marginata, distribution- modeling. Introduction Primula marginata Curtis is a chasmophyte very appreciated by horticulturists for its early pink- violet flowers and for its peculiar leaf colour and form. Its specific name is due to the conspicuous presence of a white calcareous secretion along the margins of the leaves, flower bracts, and sepals. In natural populations, the morphology of the plants may vary in colour, dimensions and shapes. However, the traits delimiting the taxon are always detectable and unambiguous. P. marginata (2n = 62 and 126; syn. P. crenata Lam, P. microcalyx Lehm) belongs to Primula sect. Auricula Duby, as clearly demonstrated by recent molecular and taxonomical investigations (Conti et al. 2000; Zhang & Kadereit 2004, 2005; Mast et al. 2006); the species resulted closely related to P. latifolia Lapeyr. (2n = 64) and these two species were identified as the possibly earliest diverging lineage in subsect. Euauricula (Zhang & Kadereit 2004). All other species belonging to the same section are distinct from P. marginata for their not mealy leaves and for the length of glandular hairs (Richards 2003). P. marginata geographic distribution range was never stated with high precision due to the frequent misidentification of the species in herbarium and literature records. In many herbaria, specimens belonging to Primula hirsuta All., P. latifolia Lapeyr., P. cottia Widmer, P. villosa Wulfen in Jacq., P. pedemontana Thomas ex Gaudin, P. apennina Widmer and P. auricula L. were often wrongly identifiedAccepted and labelled as P. marginata, resulting Manuscript in an unclear circumscription of the species range, especially in the north. The distribution ranges of some of the above mentioned species overlap that of P. marginata. For instance, in the Maritime Alps, the co-occurrence of P. marginata, P. latifolia, P. allionii and P. hirsuta has been recording for many decades. In addition, at the extremes of its range, P. marginata is in contact with P. cottia (Val Pellice), P. pedemontana (Vallée du Queyras) and P. apennina (Northern Apennines). Some karyological studies within P. marginata populations (Kress 1963, 1969) pointed out the existence of two different cytotype groups (2n = 62 and 126 respectively), the former living in the north-western side, the latter in the eastern one (Zhang & Kadereit 2005). These different cytotypes do not correspond to different morphological, genetic, and ecological groups, as confirmed by a recent study (Casazza et al. 2012). The main aims of this paper were: a) to define the detailed circumscription of the distributional range of P. marginata, verifying the presence of disjoint occurrences in northern Piedmont (Val d’Ossola) and northern Apennines (Val Nure and Val Aveto); b) to define the ecological niche of P. marginata. Materials and methods Occurrence data In order to cover all the assumed territory of the species all occurrence records of P. marginata were collected from: - the database “SILENE” of the Conservatoire Botanique National Méditerranéen de Porquerolles (CBNMED) and “FLORE” of the Conservatoire Botanique National Alpin de Gap (CBNA) in France, both exported on November 2009 (http://flore.silene.eu); - the database of the Istituto per le Piante da Legno e l'Ambiente (IPLA) in Turin (Piedmont - Italy), exported on December 2009; - the database of the Repertorio Cartografico della Regione Liguria in Genoa (Liguria - Italy), exported on June 2010; - the herbaria of Firenze (FI), Genova (GE), Torino (TO), Padova (PAD), Piacenza (PC), Portici (POR), Warsavia (WA) and the Museo Calderoni of Varallo Sesia in order to evaluate the original samples of Val d’Ossola; - bibliographical records were taken in account and geo-referenced (Appendix I and II).; - several field-trips to target areas of P. marginata were performed in 2008-2010 (Appendix III). In order to Acceptedeliminate a potential bias of occurrences indicated Manuscript more times, the datasets were filtered so that there was only one record per 0.5 km2 cell reported as centroid. These data were used in the successive analyses. The number of occurrences per each administrative area (Liguria, Piedmont and Emilia Romagna in Italy; Provence- Alpes-Côte d’Azur in France), geographical subdivision of the Alps (Marazzi 2005), thermoclimatic belts according to the Worldwide Bioclimatic Classification System methods (Rivas-Martinez et al. 2004) and substrate type (calcareous vs. siliceous - Chantraine et al. 1996) were calculated by using DIVA-GIS version 7.1.2 (www.diva-gis.org). Environmental variables The 19 bioclimatic variables (Table 1) together with elevation data (Digital Elevation Model; DEM), at 30 arc-seconds (about 1 Km2) of spatial resolution grid, were obtained from the WorldClim dataset (Hijmans et al. 2005; http://www.worldclim.org/bioclim.htm). These variables include the temperature and precipitation parameters that are biologically most meaningful to define the eco-physiological tolerances of a species (Graham & Hijmans 2006; Guisan et al. 2007a, b; Pearson et al. 2007; Kumar & Stohlgren 2009; Murienne et al. 2009). All these grids were clipped to an area circumscribed between 42° 33' to 46° 51' N and 04° 02'. to 10° 43' E (geodesic system WGS84), which spanned portions of Italy, France and Switzerland and included the alpine sectors